Data security is a critical issue for many computing devices. Computing devices can include secure processing subsystem that may be implemented as a secure area of a processor of the computing device or may include a separate processor and memory that can be used to store data. The secure processing subsystem may be implemented as a system-on-a-chip (SoC) or other similar device that includes a processor element and memory implemented on an integrated circuit. However, the amount of memory available on the integrated circuit may be limited and an external non-volatile memory (NVM) may be used to store data used by the secure processing subsystem. Confidentiality of the data stored in the NVM can be ensured through the use of encryption, and the integrity of the data stored in the NVM can be ensured through the use of digital signatures. However, an attacker may attempt to restore an old copy of the data to the NVM which is validly signed and/or encrypted by the secure processing system in what is referred to as a rollback or replay attack. Accordingly, additional protections are required for data stored in an NVM.